Laminated films of ethylene polymers and polyamide resins and laminated films of ethylene polymers and ethylene/vinyl alcohol copolymers have been conventionally known. Also, a variety of adhesive layer-forming materials used for producing the laminated films have been proposed. For example, Japanese Patent Laid-Open Publication No. 165413/1982 discloses that a modified polyethylene obtained by reacting a linear low-density polyethylene with an unsaturated carboxylic acid or derivative thereof and a modified polyethylene composition obtained by blending the modified polyethylene with a synthetic rubber and/or a linear low-density polyethylene are employable as the adhesive layer-forming materials. Japanese Patent Laid-Open Publication No. 165469/1982 discloses an adhesive resin composition obtained by modifying a mixture of a linear low-density polyethylene and a synthetic rubber with an unsaturated carboxylic acid or derivative thereof.
However, the adhesive layer-forming materials conventionally proposed have problems. For example, if the materials are subjected to stretching operation when preparing shrink films, the interlaminar strength between the ethylene polymer layer and the polyamide resin layer or the ethylene/vinyl alcohol copolymer layer may be sharply decreased, so that the resulting laminated films do not always exhibit satisfactory adhesion strength.
The shrink films are used, for example, for ham packaging various materials using an automatic packaging machine. In packaging, the film ends are heat sealed, and in the subsequent heat shrinking stage, a stress is applied to the heat sealed portions. Therefore, the shrink films are required to have high heat-sealing strength.
Moreover, in the case of food packaging, the shrink films are generally subjected to boiling sterilization treatments at temperatures as high as not lower than 80.degree. C. after the packaging, so that the shrink films are required to have resistance to high temperatures of not lower than 80.degree. C.
Accordingly, an adhesive polyethylene composition showing excellent adhesion strength to ethylene polymers, polyamide resins and ethylene/vinyl alcohol copolymers, high heat-sealing strength and heat resistance is desired. Also desired is a multi-layer laminated film wherein an adhesive layer of the composition is interposed between an ethylene polymer layer and a layer of a polyamide resin and/or an ethylene/vinyl alcohol copolymer.